From 80a4b58e36b63d7b0b592beb1bd6410aadeeb63c Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Tue, 14 Oct 2008 09:51:06 +0200 Subject: block: only call ->request_fn when the queue is not stopped Callers should use either blk_run_queue/__blk_run_queue, or blk_start_queueing() to invoke request handling instead of calling ->request_fn() directly as that does not take the queue stopped flag into account. Also add appropriate comments on the above functions to detail their usage. Signed-off-by: Jens Axboe --- block/blk-core.c | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-) (limited to 'block/blk-core.c') diff --git a/block/blk-core.c b/block/blk-core.c index 2d053b584410..91532f2d2fa7 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -325,6 +325,9 @@ EXPORT_SYMBOL(blk_unplug); static void blk_invoke_request_fn(struct request_queue *q) { + if (unlikely(blk_queue_stopped(q))) + return; + /* * one level of recursion is ok and is much faster than kicking * the unplug handling @@ -399,8 +402,13 @@ void blk_sync_queue(struct request_queue *q) EXPORT_SYMBOL(blk_sync_queue); /** - * blk_run_queue - run a single device queue + * __blk_run_queue - run a single device queue * @q: The queue to run + * + * Description: + * See @blk_run_queue. This variant must be called with the queue lock + * held and interrupts disabled. + * */ void __blk_run_queue(struct request_queue *q) { @@ -418,6 +426,12 @@ EXPORT_SYMBOL(__blk_run_queue); /** * blk_run_queue - run a single device queue * @q: The queue to run + * + * Description: + * Invoke request handling on this queue, if it has pending work to do. + * May be used to restart queueing when a request has completed. Also + * See @blk_start_queueing. + * */ void blk_run_queue(struct request_queue *q) { @@ -884,7 +898,8 @@ EXPORT_SYMBOL(blk_get_request); * * This is basically a helper to remove the need to know whether a queue * is plugged or not if someone just wants to initiate dispatch of requests - * for this queue. + * for this queue. Should be used to start queueing on a device outside + * of ->request_fn() context. Also see @blk_run_queue. * * The queue lock must be held with interrupts disabled. */ -- cgit v1.2.3 From 496aa8a98f5ab22ced46be5dc2087cdf3d029bd7 Mon Sep 17 00:00:00 2001 From: Randy Dunlap Date: Thu, 16 Oct 2008 07:46:23 +0200 Subject: block: fix current kernel-doc warnings Fix block kernel-doc warnings: Warning(linux-2.6.27-git4//fs/block_dev.c:1272): No description found for parameter 'path' Warning(linux-2.6.27-git4//block/blk-core.c:1021): No description found for parameter 'cpu' Warning(linux-2.6.27-git4//block/blk-core.c:1021): No description found for parameter 'part' Warning(/var/linsrc/linux-2.6.27-git4//block/genhd.c:544): No description found for parameter 'partno' Signed-off-by: Randy Dunlap Signed-off-by: Jens Axboe --- block/blk-core.c | 5 +++-- block/genhd.c | 2 +- fs/block_dev.c | 2 +- 3 files changed, 5 insertions(+), 4 deletions(-) (limited to 'block/blk-core.c') diff --git a/block/blk-core.c b/block/blk-core.c index 91532f2d2fa7..8517264eb71e 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -1018,8 +1018,9 @@ static void part_round_stats_single(int cpu, struct hd_struct *part, } /** - * part_round_stats() - Round off the performance stats on a struct - * disk_stats. + * part_round_stats() - Round off the performance stats on a struct disk_stats. + * @cpu: cpu number for stats access + * @part: target partition * * The average IO queue length and utilisation statistics are maintained * by observing the current state of the queue length and the amount of diff --git a/block/genhd.c b/block/genhd.c index b8defae2ec03..646e1d2507c7 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -534,7 +534,7 @@ void unlink_gendisk(struct gendisk *disk) /** * get_gendisk - get partitioning information for a given device * @devt: device to get partitioning information for - * @part: returned partition index + * @partno: returned partition index * * This function gets the structure containing partitioning * information for the given device @devt. diff --git a/fs/block_dev.c b/fs/block_dev.c index d84f0469a016..218408eed1bb 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -1262,7 +1262,7 @@ EXPORT_SYMBOL(ioctl_by_bdev); /** * lookup_bdev - lookup a struct block_device by name - * @pathname: special file representing the block device + * @path: special file representing the block device * * Get a reference to the blockdevice at @pathname in the current * namespace if possible and return it. Return ERR_PTR(error) -- cgit v1.2.3 From 713ada9ba94f2ad874cffd074b83e3dc681ca82f Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 16 Oct 2008 13:44:57 +0200 Subject: block: move q->unplug_work initialization modprobe loop; rmmod loop effectively creates a blk_queue and destroys it which results in q->unplug_work being canceled without it ever being initialized. Therefore, move the initialization of q->unplug_work from blk_queue_make_request() to blk_alloc_queue*(). Reported-by: Alexey Dobriyan Signed-off-by: Peter Zijlstra Signed-off-by: Jens Axboe --- block/blk-core.c | 1 + block/blk-settings.c | 2 -- 2 files changed, 1 insertion(+), 2 deletions(-) (limited to 'block/blk-core.c') diff --git a/block/blk-core.c b/block/blk-core.c index 8517264eb71e..fcbd56dd41fa 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -515,6 +515,7 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id) init_timer(&q->unplug_timer); setup_timer(&q->timeout, blk_rq_timed_out_timer, (unsigned long) q); INIT_LIST_HEAD(&q->timeout_list); + INIT_WORK(&q->unplug_work, blk_unplug_work); kobject_init(&q->kobj, &blk_queue_ktype); diff --git a/block/blk-settings.c b/block/blk-settings.c index b21dcdb64151..41392fbe19ff 100644 --- a/block/blk-settings.c +++ b/block/blk-settings.c @@ -141,8 +141,6 @@ void blk_queue_make_request(struct request_queue *q, make_request_fn *mfn) if (q->unplug_delay == 0) q->unplug_delay = 1; - INIT_WORK(&q->unplug_work, blk_unplug_work); - q->unplug_timer.function = blk_unplug_timeout; q->unplug_timer.data = (unsigned long)q; -- cgit v1.2.3 From f73e2d13a16cc88c4faa4729967f92bfeec8a142 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Fri, 17 Oct 2008 14:03:08 +0200 Subject: block: remove __generic_unplug_device() from exports The only out-of-core user is IDE, and that should be using blk_start_queueing() instead. Signed-off-by: Jens Axboe --- block/blk-core.c | 1 - block/blk.h | 1 + drivers/ide/ide-io.c | 4 ++-- include/linux/blkdev.h | 1 - 4 files changed, 3 insertions(+), 4 deletions(-) (limited to 'block/blk-core.c') diff --git a/block/blk-core.c b/block/blk-core.c index fcbd56dd41fa..81a496004976 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -257,7 +257,6 @@ void __generic_unplug_device(struct request_queue *q) q->request_fn(q); } -EXPORT_SYMBOL(__generic_unplug_device); /** * generic_unplug_device - fire a request queue diff --git a/block/blk.h b/block/blk.h index e5c579769963..d2e49af90db5 100644 --- a/block/blk.h +++ b/block/blk.h @@ -20,6 +20,7 @@ void blk_unplug_timeout(unsigned long data); void blk_rq_timed_out_timer(unsigned long data); void blk_delete_timer(struct request *); void blk_add_timer(struct request *); +void __generic_unplug_device(struct request_queue *); /* * Internal atomic flags for request handling diff --git a/drivers/ide/ide-io.c b/drivers/ide/ide-io.c index 77c6eaeacefa..7162d67562af 100644 --- a/drivers/ide/ide-io.c +++ b/drivers/ide/ide-io.c @@ -1493,8 +1493,8 @@ void ide_do_drive_cmd(ide_drive_t *drive, struct request *rq) spin_lock_irqsave(&ide_lock, flags); hwgroup->rq = NULL; - __elv_add_request(drive->queue, rq, ELEVATOR_INSERT_FRONT, 1); - __generic_unplug_device(drive->queue); + __elv_add_request(drive->queue, rq, ELEVATOR_INSERT_FRONT, 0); + blk_start_queueing(drive->queue); spin_unlock_irqrestore(&ide_lock, flags); } diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index a92d9e4ea96e..8eed8b15f992 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -856,7 +856,6 @@ extern void blk_ordered_complete_seq(struct request_queue *, unsigned, int); extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *); extern void blk_dump_rq_flags(struct request *, char *); extern void generic_unplug_device(struct request_queue *); -extern void __generic_unplug_device(struct request_queue *); extern long nr_blockdev_pages(void); int blk_get_queue(struct request_queue *); -- cgit v1.2.3